Use of sodium zirconium cyclosilicate for up-titration of renin–angiotensin–aldosterone system inhibitor therapy in patients with heart failure: a case series

Background Patients often receive suboptimal dosing of renin–angiotensin–aldosterone system inhibitor (RAASi) therapy over concerns of hyperkalaemia. However, studies have shown associations between suboptimal dosing or interruptions to therapy and adverse clinical events. Therefore, effective treatments for hyperkalaemia that can enable optimal RAASi therapy are needed. This case series examines eight patients whose commencement on the novel potassium binder sodium zirconium cyclosilicate (SZC) allowed for the initiation and/or up-titration of RAASi therapy. Case summary Eight patients aged 64–87 years with heart failure (HF) with reduced ejection fraction all developed hyperkalaemia (serum potassium (sK+) >5.0 mmol/L) while receiving RAASi therapy. Following initiation of SZC, all patients experienced eventual stabilization of sK+ levels. All patients were able to initiate, restart, or up-titrate RAASi therapy with five patients achieving optimal medical therapy. Left ventricular ejection fraction improved in four patients, two patients are now re-classified as New York Heart Association Class I, and an additional patient had improved exercise tolerance. Follow-up for Patient 8 is still ongoing. Discussion These real-world cases demonstrate that use of SZC to manage hyperkalaemia in patients with HF is feasible and allows optimization of RAASi therapy.